The present invention relates to a device for controlling the gas stream delivered by a pressurized gas reservoir, the pressure of the gas inside said reservoir possibly reaching several hundreds of bars. It also relates to a gas supply system comprising such a device.
Although not exclusively, the present invention is particularly well adapted for use in composite reservoirs of known type, formed of an internal liner and an external shell of filament windings coated with synthetic resin. In such composite reservoirs, the internal liner provides sealing for the gas whereas the shell of filament windings provides the mechanical strength. In addition, it is generally provided for deformation of the internal liner under the effect of the internal pressure to be of plastic type, whereas deformation of the external shell is elastic. Thus, it is possible to obtain a linear elastic deformation for the reservoir as a function of the pressure.
Because of their excellent mechanical strength and their low weight, these composite reservoirs are widely used in space techniques for storing high pressure gas (up to 800 bars). For example, they contain, oxygen, hydrogen, helium or nitrogen for the requirements of an inhabited space craft, or else they store gases for pressurizing the propulsion ergols for launchers or satellites.
Of course, in order to be able to use the gas stored in such a reservoir, it is necessary to control the gas stream leaving said reservoir. For this, a succession of controlled pressure reducers is provided, whose opening is dependant on the evolution of the pressure in the reservoir. Considering the high pressures inside the reservoir and the safety and reliability requirements in the high pressure field, such pressure reducers and their controls are heavy (of the order of 25 kg), which is highly penalizing in the space field.
To avoid the drawbacks attached to the use of such pressure reducers, they could be replaced by a system with variable flow section orifice, controlled by control electronics as a function of the internal pressure in the reservoir, measured by an appropriate pressure sensor. The total weight of the reservoir and of its operating accessories could then be reduced. However, the result would be a sophisticated, expensive construction with relatively critical operation.
Therefore, the object of the present invention is to overcome these drawbacks and provide a pressurized gas reservoir, with control of the gas stream delivered, which both avoids the use of said pressure reducers and makes it possible to obtain a simple construction with reliable operation.